1. Field of the Invention
The present invention relates to a fuel cell formed by stacking an electrolyte electrode assembly and a pair of separators. The electrolyte electrode assembly includes an anode, a cathode, and an electrolyte interposed between the anode and the cathode. Further, the present invention relates to a fuel cell stack formed by stacking a plurality of the fuel cells.
2. Description of the Related Art
Typically, a solid oxide fuel cell (SOFC) employs an electrolyte of ion-conductive solid oxide such as stabilized zirconia. The electrolyte is interposed between an anode and a cathode to form an electrolyte electrode assembly (unit cell). The electrolyte electrode assembly is interposed between separators (bipolar plates). In use, a predetermined number of the unit cells and the separators are stacked together to form a fuel cell stack.
In the fuel cell of this type, it is necessary to remove impurities such as dust from a fuel gas and an oxygen-containing gas as reactant gases. In this regard, for example, a fuel cell system as disclosed in Japanese Laid-Open Patent Publication No. 2003-317757 is known. As shown in FIG. 23, the fuel cell system includes a fuel cell 1. The fuel cell 1 includes an anode 1b, a cathode 1c, and an electrolyte membrane 1a interposed between the anode 1b and the cathode 1c. 
A reformer 2, a carbon monoxide remover 3, and an electric dust collector 4a are provided on the anode side of the fuel cell 1. The reformer 2 produces a hydrogen rich gas from a raw material gas. The carbon monoxide remover 3 removes carbon monoxide from the hydrogen rich gas. The electric dust collector 4a removes impurity particles from the hydrogen rich gas. Further, a fan 5 and an electric dust collector 4b are provided on the cathode side of the fuel cell 1. The fan 5 supplies the air as the oxygen-containing gas to the cathode 1c, and the electric dust collector 4b removes impurity particles from the air.
However, in the conventional technique, the electric dust collectors 4a, 4b are provided separately from the fuel cell 1, and spaces for providing the electric dust collectors 4a, 4b are required. Therefore, the overall size of the fuel cell system is considerably large. Further, since the electric dust collectors 4a, 4b are provided outside the fuel cell 1, it is not possible to remove dust or the like produced in the fuel cell 1.